There is an increasing need to develop improved methods and products for cleaning and disinfecting human and animal body parts, and in particular human hands. In addition to the normal need for individuals to maintain clean and disinfected hands in order to minimise the potential for transfer of pathogens, the members of a large number of professions are required to clean their hands during the course of their normal work. For example, those involved in the provision of human health care, in the preparation of food and beverage, the handling of animals, in child and geriatric care and in cleaning and waste management will all need to ensure their hands are regularly cleaned to avoid the transmission of pathogens that may cause disease either to themselves or to others. The conventional approach for hand cleaning is to use soap and water and in many workplaces where hygiene is paramount, liquid soaps or alcohol based hand rubs (gels or foams that include denatured alcohol that has been made unpalatable for human consumption) are adopted, many of which may include antimicrobial active agents such as isopropanol, chlorhexidine, triclosan, quaternary ammonium compounds, iodinated compounds and the like or parabens, glycols and synthetic fragrances. The problem with many of these agents is that they are harsh on the skin, and in the case of the antimicrobials many microbes have mutated to develop resistance to them. It is therefore desirable to develop fast acting hand cleaning formulations that exhibit high efficiency of killing or inactivating pathogens while being relatively gentle on the skin, to thereby allow for regular use (by not only trained professionals but also the general public) without development of skin irritation, inflammation, dryness, cracking, redness or an allergic response (particularly in the case of pre- and post-operative patients). Owing to some of the additives used in conventional hand cleaning formulations, it is necessary to also use a separate barrier cream and/or skin conditioner to protect and/or rehydrate the skin. Indeed the use of a separate barrier cream and/or skin conditioner is recommended by the World Health Organisation (WHO) in its “WHO Guidelines on Hand Hygiene in Health Care” published in 2009 (the disclosures of which are included herein in their entirety by way of reference) for subject susceptible to skin irritation. It would be preferable if the additional use of such barrier creams and skin conditioners was not required. Ideally, hand cleaning formulations should neither dehydrate the skin nor cause skin irritation, inflammation, dryness, cracking, redness or an allergic response.
There are also a range of settings in which it is desirable to minimise the need for the use of water in conjunction with cleansing. In terms of daily hand cleansing this is a particular issue at the moment in parts of the world where climatic and rainfall conditions are changing and where water is becoming increasingly scarce. In parts of Australia, for example, availability of water is of increasing importance due to limits being placed at least in some areas on household water consumption. It is also desirable to have access to means of effectively cleansing for military applications or in the case of activities such as outdoor labour, camping, bushwalking and the like, where limited amounts of water may be available and where any available water will be for consumption rather than for washing.
It is in this context that the present inventors have conceived a disinfecting formulation that may be used in the absence of additional water. The inventors have adopted substantially natural products that exhibit surprising efficacy against a broad range of pathogenic microorganisms, and which can be used repeatedly on human and animal skin generally without significant irritation, inflammation, dryness, cracking, redness or allergic response. There is also no evidence of the development of microbial resistance against the formulations of the invention. Primary ingredients of the formulations according to the invention include alcohol, one or more essential oils comprising cineole and a moisturiser, which is preferably a plant derived oil. Further, although it is well understood that alcohols such as ethyl alcohol exhibit antimicrobial activity (due to their ability to denature protein) it is also understood that the effects of the alcohol do not persist on the skin due to evaporation without residue. The inventors have determined, however, that other components of the inventive formulation do leave a residue, which is not unpleasant or irritant for users, but which results in persistence of antimicrobial activity on the skin surface. Thus the formulations of the invention are useful as a professional hygienic handrub, for example for health professionals, as a surgical handrub and for preoperative skin preparation for patients about to undergo surgery. It has also been observed that the formulations of the present invention improve symptoms of skin irritation and dryness that may have been caused by the application of other cleansing formulations in some subjects.
German Patent Application No. 202007002978 discloses a gel composition comprising specified amounts of alcohol, thickener, at least one active agent selected from sedatives, healing promoters and/or anti-inflammatory agents, as well as water. For effective disinfection activity this formulation appears to require the presence of biguanide compounds, phenol compounds, iodine compounds or the like, which are not required for disinfection in the present invention. In preferred embodiments of the present invention such compounds are excluded from the formulation according to the present invention, such that disinfecting activity is contributed to by essential oils and alcohol.
International Patent Publication No. WO 2005/084717 discloses a cleaning solution comprising ethanol, and essential oil with specified content of cineole. While the cleansing and disinfecting properties of alcohol such as ethanol and essential oils comprising cineole were understood, it was not expected that such agents could be combined into an alcohol based hand rub (ABHR) formulation that has moisturising properties. Before the work of the present inventors it was generally understood that it was not possible to effectively moisturise using such formulations without either compromising upon anti-microbial effectiveness or requiring the need for the inclusion of irritant anti-microbial agents such as quaternary ammonium compounds, chlorhexidine or chlorhexidine gluconate, chloroxylenol, benzalkonium chloride, fluorosalan, hexachlorophene, phenol, tribromosalan, triclocarban, triclosan and isopropanol. Indeed WHO notes in its Guideline referred to above that hand rub formulations should contain 1% to 2% of moisturiser and that adding more than 3% of moisturiser can compromise antimicrobial activity.